Process for impregnating fibrous materials and products thereof



Nov. 29, 1949 F. Y. SPEIGHT, JR

PROCESS FOR IMPREGNATING FIBROUS MATERIALS AND PRODUCTS THEREOF 4Sheets- Sheet 1 Filed Dec. 4, 1944 ATTORNEY Nov. 29, 1949 F. Y. SPEIGHT,JR PROCESS FOR IMPREGNATING FIBROUS MATERIALS AND PRODUCTS THEREOF FiledDec. 4, 1944 4 Sheets-Sheet 2 ATTORNEY Nov. 29, 1949 F. Y. SPEIGHT, JR2,489,935

PROCESS FOR IMPREGNATING FIBRQUS MATERIALS I AND PRODUCTS THEREOF FiledDec. 4, 1944 4 Sheets-Sheet 3 v I ALI'TORNEY 29, 1949 F. Y. SPEIGHT, JR2,489,985

PROCESS FOR IMPREGNATING FIBROUS MATERIALS AND PRODUCTS THEREOF 4Sheets-Sheet 4 Filed Dec. 4, 1944 Patented Nov. 29, 1949 uNiTEo STATESPATENT OFFICE Frank Y. Speight, J r., Greenwich, Conn, assignor toAmerican Cyanamid Company, New York, N. Y., a corporation of MaineApplication December 4, 1944, Serial No. 566,572

2 Claims. (01. 206-59) This invention relates to a process for applyinghot-melt resins or the like to fibrous materials and to a product orarticle of manufacture made thereby.

In the production of laminated materials bonded with substances whichare normally solid at room temperature, it would be desirable toimpregnate the fibrous material with the molten resin and to store thisin the form of a roll of impregnated material until such time as it isdesired to form a laminate, as by cutting the material into suitablelengths followed by the formation of an assembly thereof and this inturn followed by consolidation to form a laminate. This is desirableparticularly with those bonding compositions which contain a volatilereactive component. If the material, after impregnation with a materialcontaining a volatile reactive component, is permitted to cool bymerelypassing over a number of rolls or by festooning, a relatively largeamount of the volatile reactive com ponent of the bonding material maybe lost and this is not only uneconomical,.but may result in inferiorlaminates.

An object of the present invention is to provide a process forimpregnating a fibrous material with a bonding material containing avolatile reactive component, which process minimizes the loss of i saidvolatile reactive component.

Another object of this invention is to provide an apparatus for carryingout the process men- 0 tioned in the preceding paragraph.

Still another object of the present invention is to improve theimpregnationof a fibrous material such 'as glass cloth and to provide asuitable ape paratus for improving such impregnation of the fibrous Imaterial.

These and other objects are attained by apply ing a molten bondingmaterial, containing a volaf tile reactive component, to a desired andsubstantially uniform amount, and winding the imglass cloth to removesubstances which prevent good impregnation.

My invention will be more fully understood by reference to theaccompanying drawings. a

Figure 1 is an elevation partly in section showv ing one embodiment ofmy invention. Figure 2 is an elevation showing a modification of theapparatus illustrated in Figure 1. Figure 3 is a detail perspectiveviewpartly brokenaway to show the details of construction of one meansof 2 adjusting the proportions of bonding material which is retained inthe fibrous material being impregnated.

Figure 4 is an elevation partly in section showing another embodiment ofmy apparatus.

Figure 5 is a fragmentary elevation view showing in detail the roll ofimpregnated material and cover sheet produced in accordance with myprocess and by means of the apparatus illustrated in Figures 1, 2 and 4.

Figure 6 is a perspective which shows a fibrous material which has beenimpregnated and rolled up in accordance with my process and which hasbeen unrolled and the fibrous material partly separated from the coversheet.

Figure l is a schematic elevation showing one method oi utilizing thematerial produced in accordance with my invention," while Figure Bis aschematic perspective showing a modification of the method of utilizingthe impregnated material to produce laminated products in accordancewith my invention.

Figure 9 is a schematic elevation partially sectioned and it illustratesa modification of my apparatus and process wherein the fibrous materialis heated prior to impregnation. Figure 10 is a schematic elevationpartially sectioned illustrating a modification of an apparatus of thetype shown in Figure 9.

Figure ll is a schematic elevation partially sectioned showing stillanother modification of an apparatus of the type shown in Figure 9.

Referring now to Figure 1, my apparatus is composed oi a roll of,fibrous material such as glass cloth i, a roller 5 submerged in a bathof molten material. 9 contained in a tank-l. Glass cloth 3 is drawnfromroll i through the bath'oi molten material it under the'roller El andthence out of the bath through a pair of squeezerolls l5 and thence theimpregnated material t is wound on a power-driven roller llconcentrically and simultaneouslywith an impervious cover sheet it iwhich is drawn from a roller 99. This cover sheet it may be eellophaneglassine paper, wax paper,

Holland cloth, etc.

In order to maintain the molten material Q in the fluid state, thevessel l is conveniently heated by -means of a heat transfer medium suchas water or oil it which is circulated throughthe jacket ll surroundingthe vessel 8. Furthermore, inorder to supply additional quantities ofmolten material ,9, as the molten material is used I! and heated bymeans of steam coils 21. The

vessel 2| is providedwith an outlet conduit" which conduit contains avalve 3| and which conduit is adapted to feedmolten material 3 intovessel I. The heat transfer medium I3 which is circulated in the Jackets23 and II of the vessels 2| and 1, respectively, passes from jacket 23through an outlet conduit 33 and is pumped by pump 35 through conduit 31into the jacket II surrounding the vessel 1 and thence through an outletconduit 30 into one of the rolls I and from there through conduit 4|back to the space between the jacket 23 and the vessel 2| where thefluid is reheated.

Figure 2 shows a modification of the apparatus illustrated in Figure 1and differs in that the cloth 3 passes between a pair of squeeze rollsI05 which are submerged in the bath of molten material 3 and in that theimpregnated material Figure 4 in which a dry, granular resin is appliedto cloth or other fibrous material by melting on a heated pressure roll.In this embodiement of my invention, the fibrous material 3 is drawnfrom a roll I through a pain of squeeze rblls I5 which are heated bymeans of a heat transfer medium I3 flowing into one of the rolls l5,into the other roll I5 through conduit 4|, and

which causes the resinous material to cure and to thereby bond thelayers of fibrous material 4 together to form a laminated material 60which may be wound on a large roller 62 or which may be cut intosuitable lengths 64 and stacked for shipping as shown at 65 in Figure 8.When the impregnated fibrous material 4 is drawn from roll theimpervious cover sheet I8 is simultaneously stripped therefrom and woundup on roll I3. Such rewound material may be used again in ,the processand apparatus illustrated in Figures 1-4. I

Glass cloth and many other fibrous materials contain various substanceswhich are contained in the fiber when the cloth is woven in order to outthrough conduit 43. A granular resin 200 contained in ahopper '201 isfed at the desired rate by means of a'star wheel 2I0 through the .'chute2I2 onto one of the heated rolls I5 so that.

the resinous material is melted and squeezed onto the fabric 3simultaneously. pregnation of the fibrous material 3 the impregnatedmaterial 4 iS wound on to the roll I1 simultaneously with an imperviouscover sheet I3 which is drawn from a roll I9.

When the impregnated material 4 is to be used, the cover sheet I8 isstripped away from the After imformer as illustrated in Figure 6 or asillustrated in Figure 7. In Figure 7, a continuous method pass over apair of rollers 52 and a pair of rollers 56, respectively. A cover sheet(shown in broken lines for clarity) is drawn from roll 5| over thesurface of belt 50 to prevent the impregnated fabric 4 from sticking tosaid belt. The cover. sheet 55 is then rolled onto roll 53. Similarly,

a cover sheet 6| is drawn from roll 51 over belt 54 and onto roll 59.The cover sheets 55 and 5| may be cellophane, Holland cloth, wax paper,

glassine paper, etc., and may be reused Rollers 52 and 56 are spacedapart the desired distance,

to apply a low pressure to the plurality of layers of impregnatedmaterial 4 passing between belts it and 54 so that the material will bebonded together. During the passage of the material facilitate theweaving operations and/or when the fiber is spun in order to facilitatethe spinning operation. These substances often cause a non-uniform andunsatisfactory impregnation of the fibrous material and, in Figures9-11, I

have shown some modifications of my apparatus and process which aredesigned to overcome this difliculty. In Figure 9, the glass cloth 3passes from the roll I over a roller 30I and in close proximity to aplurality of infra-red lamps 303 and thence under roller 305 down intothe bath of molten material 9.

Referring to Figure 10, an embodiment of my invention showin the use ofa warm oven to remove the objectionable materials contained in fibrousmaterial to be impregnated is illustrated. Cloth 3 is drawn from roll Iand passes down over roll 40l into a warm oven 403 and thence over aseries of rolls 405 and finally out over a roller 401 and thence intothe bath of molten material 9. The oven may be heated electrically, by agas name, or by means of steam coils.

. In Figurell still another modification of my invention'is illustrated,wherein the cloth 3 is drawn from roll I and passes over roller 50I intoa housing 501. During the passage of the cloth vfinally out over roller505 and thence into the bathof molten material 9. If the cloth 3 isflammable it is fed through the housin 501 at such a rate that it willnot be damaged sufllciently when passing over the burners to render itunsuitable for its intended purpose.

The resinous material 9 may be, for example, a copolymerizable'composition containing an unsaturated substance containing the CHz=Callyl sebacate, etc. The practice of the invention is particularlyadvantageous when the more volatile of the aforementioned substances areused. The crystalline, unsaturated alkyd resins which are suitable foruse in such compositions are those which are prepared by reacting acompletely symmetrical glycol with an alpha, beta unsaturateddicarboxylic acid having a transconfiguration. Examples 'of such resinsare polyesters of ethylene glycol and fumarlc'acid, polyesters ofneopentyl glycol and fumaric acid, polyesters of trimethylene glycol andfumaric acid, polyesters of octaair for more than about to seconds.

employed for impregnating a fibrous material in accordance withmy'invention are normally solid attemperatures of 20-30F C. but melt attemperatures between about 50 C. and about 100 C.

or higher. Accordingly, a bath of molten material 9 or the solidmaterial 209 shouldbe heated to whatever temperature is required tomaintain it in a molten condition but the temperature.

should preferably not be much higher inasmuch as the substancecontaining the CH2=C group is volatile and will be partly lost ifthe-temperature is too high. Furthermore, the time, between that whenthe impregnated cloth leaves-the bath of molten material 9 until it iswound up and coveredby the impervious cover sheet ll, should be kept ata minimum in order to avoid the loss of the V012.- tile material whilethe resin is still hot and while a large surface is exposed. This timeshould not be greater than about 20 seconds and is preferably.

below 5 seconds. If the distance between the wind-up roll l1 and thebath of molten material 9 (or the rolls II in the modification shown inFigure '4) be relatively short, the fabric being impregnated can bepassed relatively slowly through the bath of molten material a withouthaving the impregnated materiaiexposed to the This will give sumclenttime for a thorough impregnation of the fibrous material and at the sametime keep the loss of the volatile component of the resinous mixture ata minimum.

While I have described my process and apparatus primarily in connectionwith the impregnation of glass cloth, other types of fibrous materialmay be'impregnated in the same manner and with the same apparatus. Thus,for example, cloth or paper made of glass fibers, asbestos fibers,cellulose fibers, artificial fibers such as "nylon" and other syntheticpoLvamide fibers,. cellulose acetate, regenerated cellulose,-polyvinylidene chloride fibers such as those sold under the tradenameSaran," etc. The fibrous material may contain mixtures of any of theforegoing fibers or mixtures of any of those fibers with other fibers.

The heat treatment of the fibrous material illustrated in Figures 9-11is especially useful in connection with the impregnation of glass clothsince glass cloth ordinarily contains certain chem- 6 be taken toprevent undesirable damage to the fibers. In other words, the time ofexposure to the heat treatment should generally be much less withinflammable-material, and the temperature should be lower than thatwhich can be used with the non-inflammable fibers.

The impregnation of the fibrous material is facilitated particularlybecause of the fact that air entrapped in the fabric is squeezed out ifa plurality of rolls I05, shown in Figure 2, be used in the impregnatingbath. If desired, cloth may be passed between three or more rolls inorder to secure better and more uniform impregnation of the fibrousmaterial. v

The proportion of resinretalned in the fabric after impregnation isadjusted by means of rolls l5 or by means of the presser feet; I I5 andthese are heated in order to prevent the resin from solidifying thereonand in order to cause the excess resin which is removed to fall backinto the vessel 1.

'1. An article of manufacture comprising a roll of alternate, spiralconvolutions of fibrous material impregnated with a copolymerizablecomposition and a removable, non-adhering sheet of relatively imperviousmaterial, said copolymerizable composition containing a predominantproportion of an unsaturated allwd resin solid at room temperature inadmixture with a styrene. said resin having been prepared by reacting acompletelysymmetrical glycol with fumaric acid in approximatelyequimolar proportions, said sheet of impervious material substantiallypreventing loss by volatilization, of the styrene.

2. An article of manufacture according to claim 1 wherein the removablenon-adhering sheet of I relatively impervious material is cellophane.

FRANK Y. :SPEIGHT, J R.

REFERENCES crrnn The following references are of record in the file ofthis patent:

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